Lubricant oil composition



United States Patent 3,385,791 LUBRICANT OIL COMPOSITIGN Charles C.Colyer, Crown Point, Walter W. Frank and John V. Peterson, Portage, andWilliam L. Sieker, Crown ioint, Ind, assignors to Standard Oil Company,Chicago, llL, a corporation of Indiana No Drawing. Continuation-in-partof application Ser. No. 441,841, Mar. 22, 1965. This application Sept.15, 1967, Ser. No. 668,165

3 Claims. (Cl. 25232.7)

ABSTRACT OF THE DISCLOSURE High severity service function over extendedoil drain range, e.g., 2,500 to 6,000 mile, recommended by manufacturersof automobile engines having positive crankcase ventilating devices isprovided by crankcase lubricating oil formulations having an essentialcombination of three additive components dissolved in hydrocarbon oilsof lubricant oil class. The essential combination is (a) oilsolublenitrogenand boron-containing dispersant-detergent having a weight ratioof nitrogen to boron in the range of 0.1 to 0.5 weight percent nitrogenper Weight percent boron that are boric acid berated disuccinimides of abis(polyaminoethyl)symmetrical urea, (b) oil soluble calcium ormagnesium sulfonate of high alkalinity such as those having a total basenumber of at least 300, and (c) oil-soluble zinc dialkyldithiophosphateswhose two alkyl groups are of different carbon contents with one alkylgroup having three or four carbons and the other alkyl group beingprimary alkyl with from five to ten carbons. The three additives arepresent in the concentrations to provide on the basis of 100 gallons ofoil from 3 to 20 pounds of (a), an amount of (b) equivalent to 1.05 to3.2 pounds of calcium and an amount of (c) to provide 0.25 to 1.2 poundsof zinc. Dispersant-detergent (a) is, for example, derived by boric acidboration of the disuccinimide product of the reaction between two molesof 400 to 2,900 molecular weight polybutenyl substituted succinicanhydride with one mole bis(polyaminoethyl) urea under conditions forsplitting out and removing water of reaction. Thebis(polyaminoethyl)urea is the product of reacting two moles ofpolyethylene polyamine (cg, tetraethylene pentamine) with one mole ofurea with the splitting out and removal of two moles of ammonia.

Related application This application is a continuation in part of ourearlierfiled application Ser.. No. 441,841, filed Mar. 22, 1965 and isnow abandoned.

Background of the invention This invention relates to lubricant oils.More particularly, it concerns the provision of a lubricant oilcomposition containing an essential combination of additives whosefunction is not only to protect the lubricated parts of an internalcombustion engine but also protects positive crankcase ventilator valvesfrom malfunction.

During the past half century, increasingly severe requirements have beenimposed on lubricant oils for internal combuston engines. As engineperformance was increased, so also were the various specifications onmotor oil performance.

Beginning about 1946, engine performance levels were elevated sodrastically that entirely new lubricant performance tests had to bedevised, An oil that was entirely satisfactory for all auto-mobilemodels in one year would, because of higher cylinder compression ratios,higher engine temperatures, higher frictional loads on bearings andother surfaces, and other factors, fail to meet the standards of thenext years models.

Until 1961 the formulators of motor oils had little difiiculty keepingpace with increasing requirements of higher performance engines. True,some oils performed better than others, and a few were even ahead of themarket requirements.

But in 1961 and 1962 the picture changed drastically. Americanautomobile manufacturers announced that henceforth they wererecommending crankcase oil changes considerably in excess of the 1,000or 2,000 mile changes advised by the manufacturers. With thisrecommendation facing them, producers of motor oils were faced with therealization that no existing motor oil could be expected to meet thegreatly extended oil-drain specification recommended. Additivespreviously used to improve various aspects of motor oil performancewould provide but a starting point for the development of oils capableof functioning for the newly suggested mileage extension between oilchanges, up to 6,000 mile requirement between crankcase lubricant oilchanges.

The problem of providing an extented service motor oil formulation is aserious one. In essence, an oil must be capable of providingsatisfactory lubrication for a period of from three to six times as longas had been required in the past. At the same time it must maintain thecrankcase as well as other parts of the engine free of harmful sludgedeposits, and must afford protection against rust and corrosion as wellas wear protection for engine parts such as valve lifters which are inextreme contact pressure. Moreover, long service motor oils must retainthe characteristics of suitability for diesel engines as well asspark-ignition engines such as oxidation stability, viscositymaintenance, cold starting characteristics, certain combuston chambercontrol features, and oil mileage and fuel economy which consumers havecome to expect from all premium grade oils. While additives are knownwhich are capable of increasing one or perhaps two of thesecharacteristics, there are many sources of specific interactions withother lubricant additives that only careful and extensiveexperimentation leads to truly useful motor oil formulations suitablefor the more severe extended service.

At about the same time of the announced intent to recommendsubstantially increased mileage use of crankcase lubricating oilcompositions, there were also announced regulatory measures to beimposed on the operation of internal combustion engines in an attempt toreduce air pollution by engine combustion by-products which were allegedto be the source of irritants to eyes and the respiratory system and tocontribute in large urban areas to the atmospheric condition known assmog. It has been known for some time that combustion chamberby-product-s are forced past piston rings. which function to seal thecombustion chamber of the cylinders from the crankcase. The crankcase ofan intenal combustion engine normally vented at atmospheric pres-surewas at a much lower pressure than either the pressure of the compressedmixture of air and fuel, 120 p.s.i.g. and higher, in the combustionchamber before ignition of the fuel therein or of the hot expandinggases therein during combustion providing the power stroke drivingforce. The substantial pressure differential permitted the blow-by ofcombustion mixture and combustion by-products from the combustionchamber to the crankcase.

One of the aforementioned regulatory measures was directed against thedirect venting of the crankcase to the atmosphere and requiredreintroduction of the blowby vapors and/or gases into the combustionchambers for more complete burning thereof to less obnoxious products.Another regulatory measure was directed to the treatment of the exhaust,combustion chamber combustion products discharged to the exhaustmanifold and thence to the atmosphere. The ultimate solution was toachieve a higher degree of engine waste product conversion to at leastless harmful products. Crankcases could be ventilated to the air intakesystem before or after carbureting the air with the hydrocarbon fuel.crankcase ventilation into the intake air filter or between the filterand carburetor causes the deposition of solids, e.g. carbon particles,entrained in the gases and/ or vapors from the crankcase in the airfilter or on parts of the carburetor having close operating tolerancesthereby causing plugging of the air filter and/or the carburetor.Furthermore, such venting methods were not always positive and complete.

The crankcase could be positively vented by connecting the crankcasevapor space to the fuel-air intake manifold which is at subatmosphericpressure during engine operation because of the suction caused by theintake stroke of the piston-s. The pressure in the fuel-air intakemanifold decreases as the engine speed increases and a reduced pressurecan be obtained which would cause a large portion of the liquidcrankcase lubricant composition to be drawn out and charged with thefuel-air mixture into the combustion chambers. Drastic lubricationfailures would thereby result. To prevent this removal of crankcaselubricant at the lower intake fuel-air manifold pressures a valve isplaced in the ventilating line between the crankcase and the intakemanifold to control the pressure between the crankcase and said intakemanifold but still permitting the positive ventilation of the crankcase.Such a valve is referred to as a positive crankcase ventilator valve andis hereinafter designated PCV valve. The PCV valve is designed tooperate completely open when the engine -is not operating or at idle andthen gradually restrict flow to throttle the pressure differential asthe engine speed increases. The PCV valve never completely closes.

The gases and/or vapors from the crankcase contain sludge and varnishformers, water vapor, corrosive vapors and solids entrained in the gasesand/ or vapors. Thus the PCV valve can become fouled and renderedinoperative from sludge and/ or varnish deposit-s, corrosion and rust.Sludge and/or varnish deposits in the intake manifold or on the intakevalves and valve seat surfaces and corrosion or rusting of the valveseats adversely impair the operation of the internal combustion engine.Also, the same sludge and/or varnish formers as well as suspended finesolids enhance the formation of deposits on the upper surfaces of thecombustion chamber and piston thereby requiring an increase inanti-knock requirement of the fuel for satisfactory smooth engineoperation. Thus a still more severe requirement is placed on thecrankcase lubricating oil composition by the PCV valve over and abovethose already imposed by increased heat and oxidation stability, Wear,rust, depositing of sludge and varnish and corrosion in the enginebecause of longer oil use at higher maximum tetnperatures, increasedstop and go driving as well as intermittent engine operation duringwhich the engine barely reaches operating temperature and then is shutoff. The crankcase lubricant oil must not only function for a greatlyincreased mileage between drains but also must prevent malfunction ofthe PCV valve by pre- 4 venting materials which would corrode and/ordeposit in or on the valve from reaching the PCV valve.

There has now been discovered a motor oil which satisfies therequirements of oils for extended drain periods now being recommended byengine builders and prevents the malfunction of the PCV valves. Inaddition to retaining the features possessed by conventional premiumgrade motor oils, the motor oil of the invention provides durability,resistance to oxidation, corrosion, rust, wear, sludge and varnishdeposition and protection of the PCV valves against malfunction to adegree unapproached by closely related motor oil formulations.

Summary of the invention According to the invention, the novel motor oilcomprises a mineral lubricating oil base having as essential additives aparticular combination. of (a) a nitrogenboron containing reactionproduct detergent-dispersant, (b) a calcium or magnesium salt of anoil-soluble organic sulfonic acid having a total base number of at least300 mg. KOH per gram and (c) a heat stable zinc salt of a dialkyldiester of dithiophosphoric acid. The oil also advantageously containsone or more viscosity index im provers and an anti-foam additive.

As indicated, the oil of the invention comprises a mineral base with acombination of three essential additive components in a particularcombination. This combination provides for each gallons of formulatedoil (a) in the range of from 3 to about 20 pounds of the nitrogen boroncontaining reaction product detergent-dispersant, advantageously a boroncontaining derivative obtained from an alkyl substituted succinic acidor anhydride and a polyam-ino urea, (b) an amount of Ca or Mg 300 totalbase sulfonate to provide the chemical equivalent of 1.05 to 3.2 poundsCa, and (c) a zinc salt of a dialkyl (one C to C alkyl and one C to Calkyl) dithiophosphoric acid in an amount to provide 0.25 to 1.2 poundsof zinc. Such zinc salt preferably has primarily primary alkyl groups ofoptimum heat stability. Typically the alkyl groups of the zinc salt aremixtures of isopropyl with primary amyl, octyl and decyl and isobutylwith primary amyl, octyl and decyl with at least 55 mole percent primaryalkyl. Additionally the composition advantageously contains apolyisobutylene viscosity index improver and/ or a polymethacrylateviscosity index improver, and a silicone anti-foam agent. Concentratesof the combination of additives dilutable with lubricant base oil stockto the aforementioned concentrations are also contemplated.

In the ensuing portions of this specification the several components ofthe motor oil formulation of this invention will be discussedindependently and illustrative detailed specific compositions Will bepresented. Then, the results of testing this specific formulation willbe presented and discussed.

The tests to which the present lubricant oil are subjected areexceptionally severe. In respect to the properties of engineperformance, oxidation stability, oil mileage, cold starting ability,fuel economy, and combustion chamber control, the lubricant oilcomposition of this invention is required, of course, to at least equalthe performance of a formulated motor oil that has been approved andaccepted on the basis of its performance for engine lubrication. Withrespect to the properties of long crankcase life, rust protection andwear protection, engine cleanliness, PCV valve protection as Well asconformity to SAE 10W-30 requirements, the inventive motor oil isrequired to surpass commercially available premium grade oils by asubstantial margin.

Lubricant base oil The base oil in which the aforementioned combinationof essential additive ingredients is dissolved is a petroleumderivedlubricant vehicle, preferably one which has been solvent extracted withphenol, furfural, and the like and/ or propane dewaxed to improve itstemperature-viscosity performance. The oils generally are in thelubricating oil viscosity range; e.g., from about 50 SSU at 100 F. toabout 300 SSU at 210 F., but normally are required to conform to moreexacting specifications for motor oils of a particular service, as forexample to the various Society of Automotive Engineers tests.

The base oil will usually constitute from about 75 to about 85 volumepercent of the formulated lubricant, but this percentage may be eitherlower or higher, e.g., 5090 volume percent, depending upon the amountsof the respective additives.

In addition to petroleum hydrocarbon sources, synthetic lubricants ornatural hydrocarbons other than those petroleum derived can also be usedto provide the base oil. Hydrogenated coal derived hydrocarbons suitablyconverted, by methods known to the art, to hydrocarbon oils of desirableviscosity index characteristics, shale oil, polybutenes, etc., can alsobe used for this purpose.

Nitrogen and boron-containing reaction products derived from alkenylsubstituted succinic acid or anhydride An essential compound of thecombination of additives for the lubricant oil formulations of thisinvention is the nitrogen-boron containing alkenyl substituted succinicacid or anhydride derived reaction product dispersant detergent. TheseN-B-containing dispersant detergents are desirably present in aconcentration in the range of from about 3 to pounds per 100 gallons ofthe formulated lubricant and are preferably present in concentrations inthe range of 9 to 17 pounds per hundred gallons of the formulatedlubricant oil.

A wide variety of N-B-containing dispersant-detergent additives can beused but the preferred additives of this class are derived from alkenylsubstituted succinic acid or anhydride having or more carbon atoms inthe alkenyl hydrocarbon substituent. These N-B-containingdispersant-detergents are prepared by reacting a polyamino urea with thealkenyl substituted succinic acid or anhydride (an alkenyl succinic acidproducing compound) at a temperature in the range of about 170 to 485 F.to form a di(alkenyl succinimide) of the polyamino urea as a firstreaction product. Then the first reaction product is reacted at atemperature in about the same temperature range (i.e., 170 to 485 F,preferably 250 to 350 F.) with a boron compound such boron oxide, boronhalide, boron acids and esters of boron acids, preferably boric acid.

The polyamino urea reactants are not a new composition of matter. Theirpreparation is described in US. Patent No. 2,644,759 where the polyaminoureas are characterized as pigment wetting agents useful in thepreparation of printing inks. Polyamino ureas preferred as reactants forthe above N-B-containing dispersant-detergent are the polyamino ureasprepared by reacting an alkylene amine with urea in the ratio of twomoles alkyl amine per mole urea. Reaction between the alkylene amine andurea liberate two moles of ammonia per mole of urea and is suitablycarried out at a temperature above 200 F. and preferably in the range of250 to 350 F. The reaction product is a symmetrically substituted ureaand can be described as having two alkylene amine rnoieties joined byone carbonyl group:

Each of the valences of the carbonyl carbon are attached to one nitrogenof one mole moiety of the alkylene amine.

The foregoing N-B-containing disuccini-mides of polyamino ureas aredispersant-detergent additives having suitable oil solubility even forpreparing concentrates when obtained from alkenyl substituted succinicacids or anhydrides having in the alkenyl hydrocarbon substituent groupat least 30 carbon atoms and desirably from 30 to 200 carbon atoms. Thealkenyl hydrocarbon substituent group is preferably that resulting fromthe reaction of a liquid viscous polybutene of the aforementioned carboncontent with 'maleic anhydride.

The alkylene amine reactant for the preparation of the polyamino ureaused to obtain the N-B-containing dispersant-detergent additives ispreferably an ethylene amine of the class represented by the formulawherein x is from 1 to 10. These ethylene amines include ethylenedia'rnine, and such polyethylene polyamines as are obtained by reacting3 to 10 moles of ammonia with 2 to 9 moles of 1,2-dichloroethane.Polyethylene polyamines having 3 to 6 nitrogens (x is 3 to 6 in theformula) are preferred of the ethylene amines and these are exemplifiedby diethylene triamine, triethylene tetramine, tetraethylene pentamineand pentethylene heXa-mine. Such polyethylene polyamines might also benamed amino-polyazethyl amines. Thus the preferred polyamino ureas mightalso be named 1,3-bis(a-aminoethyl-[i-polyazethyl)ureas to indicate thatthey have at least one terminal -NH group on each ethylene amine moietyattached to the carbonyl carbon of the urea.

The N-B-containing dispersant-detergent additives are suitably preparedby reacting about two moles (1.8 to 2.2 moles are desirable and 2.0moles are preferred) of alkenyl substituted succinic anhydride per moleof polyamino urea and from 0.4 to 1.5 gram atoms of boron compound pergram atoms of nitrogen of the ethylene amine reactant. The preferredN-B-containing dispersant deter-gent has a boron content expressed asthe ratio of weight percent boron (B) to weight percent nitrogen (N),thus B/N weight ratio, in the range of 0.2 to 0.3. Suitably the B/Nratio can be 0.1 to 0.5.

Generally, the alkenyl substituted succinic acids and anhydrides can bereacted with the polyamino urea reactant in the presence of a reactiondiluent. A volatile solvent such as toluene or xylene can be used as thediluent. The volatile solvent is removed at the end of the reaction toaid in the removal of by-product water. Less volatile solvents such asthe liquid viscous polyolefins, liquid viscous polypropylenes andpolybutenes, and/ or low viscosity lubricant base light oil blendingstocks such as an SAE5 solvent extracted mineral oil can beadvantageously used as reaction solvents because they need not beremoved from the product resulting from the reaction of the substitutedsuccinic acid and/ or anhydride and polyamino urea. The reaction of theboron compound with the product resulting from the reaction of thesubstituted succinic acid and/ or anhydride with polyamino urea can beconducted in the presence of the less volatile solvents. It isadvantageous when the substituted succinic acid and/or anhydridereaction product with polyamino urea is prepared in a volatile solvent,to carry out the boration step (reaction with the boron compound) andthen remove the solvent. But when using the preferred boron compound,boric acid, it is preferred to prepare the NB-containin-gdispersant-detergent additives by reacting the substituted succinic acidor anhydride, polyamino urea and boric acid in the two reaction steps inthe presence of the less volatile solvents retainable in the finalproduct and remove only 'by-product water. Thus the N-B-containingdispersantdetergent additives are obtained as solutions thereof inliquid viscous polybutenes and/ or light mineral oil blending stocks ina concentration in the range of 25 to 70, preferably 40 to 60, weightpercent of the dissolved N-B- containing dispersant-detergent additive.

The following prepartion is illustrative of the aforementioned solutionsof the N-B-containing dispersantdetergent additives useful according tothis invention.

Dispersantxletergent solution To a 3,000 gallon kettle vented through astack to the atmosphere there is charged 1,254 gallons (9,600 pounds) ofa solution of polybutenyl substituted succinic anhydride having amolecular weight of about 960. This solution contains 54 weight percentof the substituted succinic anhydride dissolved in a mixture of 860molecular weight polybutene and solvent extracted SAE W oil. Thus, 5.4moles of the polybutenyl succinic anhydride are charged. Also charged tothe kettle are 339 gallons of additional solvent extracted SAE 5W oil.The resulting mixture is heated to 250-260 F. while blanketed with aninert gas such as nitrogen. Thereafter 122 gallons (1,095 pounds or 2.7pound moles) of a polyam-ino urea. (obtained by reacting in the ratiotwo moles tetraethylene pentamine with one of urea under conditionssplitting out and removing two moles of ammonia per mole of urea) ispumped in over 60 minutes. This d-i(pentamino)urea, 1,3- bis(tet raethyltetraamino)urea, has a nitrogen content of about 30.5%, a total basenumber (MgKOH/gram) of about 815, a SSU viscosity at 210 F. of about 72,a gravity of about 9.0 and a 365 F. flash point. The reaction mixture isheated to 300 F. and held at this temperature for about 2 hours whilesparging nitrogen through the reaction mixture to aid in the removal ofby-product water, about 97 pounds.

There is combined with the resulting solution of disuccinimide ofdi(pentamino)urea 600 pounds of boric acid slurried in 150 gallons ofsolvent extracted SAE 5W oil. The slurry of boric acid in oil is addedas rapidly as possible without causing excessive foaming by liberationof water vapor. Thirty minutes is a suitable boric acid slurry additiontime. The slurry preparation vessel and charge line are Washed with anadditional 100 gallons of SAE 5W oil and this 100 gallon wash goes intothe reaction vessel. The resulting mixture is held at 300 F. for onehour. Nitrogen is then sparged into and through the reaction mixture for2 hours at 300 F. to dry the reaction mixture. Thereafter the product(solution of N-B-containing dispersant-detergent) is filtered with afilter aid and cooled to ambient temperature. The product contains about40 Weight percent of the borated disuccinimide of di(pentamino urea),has a nitrogen content of 2.07 weight percent, a boron content of 0.58weight percent, a B/N weight ratio of 0.28 to 1.0, a gravity of 7.68pounds per gallon, a SSU viscosity at 210 F. of 900 and a flash point of380 F.

In a like manner N-B-containing dispersant-detergents having a B/N ratioof 0.1:1 to 0511 can be prepared by suitable adjustment of the amount ofboric acid used. Also the NB-containing dispersant-detergent can beprepared in like manner from polyamino ureas derived from reaction ofdiethylene triamine, triethylene tetramine, pentaethylene hexamine andmixtures of polyethylene polyamines (those four polyethylene polyaminesplus tetraethylene pentamine) having the nitrogen content in weightpercent equal to the weight percent nitrogen in pure tetraethylenepentamine. Such a mixture is commercially available under various tradenames and is believed to be the partially distilled product from thereaction of 1,2-dichloroethane and ammonia using an excess ofdichloroethane. Moreover, in like manner solutions of N-B-containingdispersant-detergent can be obtained from polybutenyl succinic anhydrideof molecular weight in the range of about 495 to about 2,900 in place ofthe 960 molecular weight polybutenyl substituted succinic anhydride ofthe illustrated process.

Highly basic calcium or magnesium oil-soluble sulfonates The calcium andmagnesium oil-soluble sulfonates used to prepare the compositions ofthis invention have a total base number of at least 300. Such analkalinity is in excess of the normal or just neutralized sulfonicacids. Consequently, the calcium and magnesium sulfonates of such highalkalinity are prepared in a solvent, generally a light mineral oilblending stock such as SAE-5W. Concentrates of such highly alkalinecalcium and magnesium sulfonates containing 30 to 40 weight percent ofthe calcium and magnesium sulfonate soaps are usually prepared. The

high alkalinity is provided by adding to a solution of an oil-solubleorganic sulfonate such as mahogany acids, sour oils, sulfonic acidsderived from the sulfonation of alkylated benzenes and especiallyalkylated benzenes boiling higher than alkylated benzenes havingpropylene tetramer or butylene trimer alkyl substituent groups.Preferably the sulfonates are derived from sulfonic acids having 30 to200 alkyl carbon atoms. The solutions of such organic sulfonic acids areadmixed with dispersions of calcium hydroxide containing an excess ofcalcium hydroxide over that stoichiometric amount to neutralize thesulfonic acids. Through various techniques, for example, by addingcarbon dioxide or ammonium carbonate, the excessive quantities ofcalcium hydroxide are converted to very finely dispersed calciumcarbonate. A typical highly alkaline calcium sulfonate is as follows:

Calcium sulfonate soap 30 weight percent.

Total calcium 11.5%. Total base number 300 milligrams KOH per gram.Specific gravity 9.4 pounds per gallon.

The highly alkaline magnesium sulfonates are prepared in a similarmanner substituting for calcium hydroxide, of course, magnesium oxide orhydroxide in amounts necessary to provide solutions containing themixture of magnesium soap and dispersed magnesium carbonate in an amountto provide a total base number of at least 300 milligrams KOH per gramof solution. The use of highly alkaline magnesium sulfonates having atotal base number of at least 300 are preferred for use in formulatinglubricant oil compositions to be used as crankcase lubricants for sparkignited automobile engines.

Zinc dialkyldithiophosphate additive As hereinbefore stated, the Zincdialkyldithiophosphate component of the novel combination of lubricantoil additives are those zinc dialkyldithiophosphates obtained fromdialkyldithiophosphoric acids having in their alkyl groups a mixture ofisopropyl groups and primary alkyl groups of from C to C or a mixture ofsec. butyl and C to C primary alkyl groups. In general, the primaryalkyl groups are those obtained from the C to C oxo alcohols.

These zinc dialkyldithiophosphates are generally prepared in thepresence of lubricant mineral oil blending stock.

Exceptionally useful zinc dialkyldithiophosphates for the purposes ofthis invention are those having alkyl groups in the ratio of 65 molepercent isopropyl and 35% oxo-decyl, 44 mole percent isobutyl and 56mole percent primary amyl, 65 mole percent isobutyl, 25 mole percentprimary amyl and 10 mole percent oxo-octyl and 60 mole percent isobutyl,35 mole percent primary amyl and 5 mole percent oxodecyl.

Typical of the foregoing zinc dialkyldithiophosphates are those havingthe following compositions and specific gravities.

Weight percent Zn 6.41 Weight percent P 5.56

Weight percent S 11.12 Pounds per gallon 8.57

Weight percent Zn 8.07 Weight percent P 7.00 Weight percent S 14.00Pounds per gallon 9.01

Weight percent Zn 9.22 Weight percent P 7.00 Weight percent S 14.00Pounds per gallon 16 The foregoing three solutions of zincdialkyldithiophosphate contain about 58 weight percent, 73 weightpercent, and 83 weight percent zinc salt.

Preferred embodiments To illustrate lubricant compositions of thisinvention the following lubricant oil formulations are given.

EXAMPLE 1 An SAE grade 10W-30 oil is formulated from the followingingredients:

Volume percent SAE-5W base oil 43.2 SAE-10 base oil 40.0 N-Bdispersant-detergent 5.0 High alkalinity magnesium sulfonate 2.0 Zincdialkyldithiophosphate (type B) 0.8 Viscosity index improver (polybutenetype) 7.0

The N-B dispersant-detergent used in the foregoing formulation isobtained from the reaction of polybutenyl succinic anhydride (molecularweight of about 860) with polyamino urea from tetraethylene pentamineand with boric acid as reactants. The dispersant-detergent has a B/Nratio of 0.247:1.0.

This formulated lubricating oil composition has the following typicalinspections.

Typical inspections Gravity, API 29.1 Flash, F 400 ASTM pour, F. 35Extrapolated viscosity, F., SUS 10,000 Viscosity, 100 F., SUS 320Viscosity, 210 F., SUS 63.5

Cold crank at 0 F 11,000

Zinc, percent wt. 0.093 Phosphorus, percent wt. 0.082 Sulfur, percent wt0.38 Magnesium, percent Wt 0.18 Nitrogen, percent wt. 0.093 Boron,percent wt 0.023 ASTM D664 Method total base number 7.5 Sulfated ashcontent, percent wt. 1.0

EXAMPLE 2 An SAE grade 5W-20 lubricating oil formulation is preparedfrom the following ingredients:

Volume percent SAE-5 base oil 86.2

N-B containing dispersant-detergent 5.0 High alkalinity magnesiumsulfonate 2.0 Zinc dialkyldithiophosphate (type B) 0.8 Viscosity IndexImprover (polyacrylate type) 6.0

In the foregoing formulation the same solution of the N-Bdispersant-detergent described in Example 1 is used.

Typical inspection values for this lubricating oil composition are:

Typical inspections EXAMPLE 3 An SAE 20W40 oil is formulated from thefollowing ingredients:

Volume percent SAE-l0 base oil 15.0 SAE20 base oil 73.2 N-Bdetergent-dispersant Solution (N/B=O.247/1.0) 5.0 High alkalinitymagnesium sulfonate 2.0 Zinc dialkyldithiophosphate (type B) 0.8Viscosity Index Improver (polyacrylate type) 4.0

Typical inspection values for this lubricating oil composition are:

Typical inspections Gravity, API 27.2 Flash, F. 455 ASTM pour, F. 20Viscosity, SUS:

Extrapolated, 0 F. 32,000 Cold crank, 0 F.:

100 534 210 75.1 Zinc, percent wt. 0.093 Phosphorus, percent wt 0.082Nitrogen, percent wt. 0.093 Boron, percent wt. 0.023 Magnesium, percentwt. 0.18 Sulfur, percent wt 0.42 D-664 TBN mg. KOH/gm. 7.5 Sulfated ash,percent wt. 1.0

Such formulations (Examples 1, 2 and 3) used in the Lincoln Sequence Vengine test, hereinafter described, give total sludge ratings values of45 to 48 and total varnish ratings in the range of 38 to 42. When usedin the PCV valve test in fleet operated vehicles, PCV valve plugging isnot encountered even at 10,000 miles of operation without change.

Rust prevention tests To evaluate the ability of formulated lubricantoil of Example 1 to inhibit engine rusting, the Oldsmobile MS SequenceII (for low temperature rust and corrosion) and III (for hightemperature oxidation) tests, in modified form, were selected. These MStests were developed by Detroit automobile manufacturers to define theminimum performance requirements of oils classified for service MS foruse with automotive gasoline-powdered engines. Test conditions for thetwo Oldsmobile sequences are shown below. In each test a standardizedfuel is used.

Test conditions are shown below.

MS test conditions [Engiue-1904 V-8 Oldsmobile Engine with Two-barrelCarburetor] II III Test Sequence Operating Conditions:

Speed, r.p.m 1, 500= =20 3, 400 20 Load, blip 25* *2 Coolant Out,Coolant: In, T. Oil Sump, F. Air-Fuel Ratio... Intake AIir Humidity,grains/lb. of dry air at Oil Consumption, Qts Blow by rate, c.f.m. at F.and 2 1 Mercury Orankease oil filter tube removed and plugged- TestSchedule, Hours 20 Oil Filter Maximum.

The results of these tests are as follows:

Oil used in Example 1:

Varnish deposits Baflle (Bottom) Piston skirts, avg. Rocker arm coverOil used in Example l:Cn/i/1ucd Varnish deposits C0nti/zz:ed

Top engine cover 9.5 Oil pan 9.2

Total 47.3

Average 9.5 Sludge deposits Rocker arm covers 9.5 Top engine cover 9.6Oil pan 9.5 Rocker cover 9.7

Total ('4 of sum) 48.0

Average 9.6

Total varnish and sludge 95.3 Rust Valve lifter bodies 8.9 Valve lifterplungers 9.3 Valve lifter ball checks 9.4 Pushrods 9.1 Relief valveplunger 9.3

Average 9.3 Lifter plunger sticking None Scuffing cam noses and liftersNone Avg. Cu Pb bearing Wt. loss, mg. 17 Wear, inches:

Avg. combined cam and lifter 0.0023 Max. combined cam and lifter 0.0031Oil consumption, qts. 6.3

1 Evaluations made visually and ratings assigned on a scale of 0 toWhere 10 is no varnish, sludge or rust, 1.8. part examined is clean.

Lincoln Sequence V Test The Lincoln MS Test Sequence V developed by FordMotor Company, tests the low temperature disperancy characteristics of alubricating oil. Briefly the test consists of using the oil to be testedas a lubricating oil in a V-8 Lincoln engine under prescribed testconditions. Accordingly, five quarts of oil are placed in the crankcaseand the engine is started and run in accordance with the four hourcycle:

The four-hour cycle is repeated four times a day followed by an 8-hourshutdown. A total of 48 cycles, 192 hours total running time, are madeand the engine is disassembled and inspected. Oil consumption should notexceed 8 quarts for 192 hours running time. The disassembled engineparts are inspected for deposits of varnish and sludge among otherobservable results as set out in the table below. Engine components areexamined visually and rated on a scale of 1 to 10, 10 being a perfectreading indicating no sludge or varnish. A rating of 50 for total sludgeand for total varnish is con sidered perfect; a rating of 10 for pistonvarnish is considered perfect; a rating of 60 percent or lower isconsidcred passing for screen clogging; and a rating of 50 percent orlower is considered passing for a ring plugging.

In this test the formulated lubricant oil composition of Example l isused and compared with two other lubricant oil formulations. The firstcomparative lubricant oil formulation has a composition similar tolubricant oil formulation of Example 1 except that thedetergent-dispersant is a boric acid borated product of an 860 molecularweight polybutenyl succinic anhydride reacted with tetraethylenepentamine in a mole ratio of two moles of the substituted anhydride permole of the polyamine and the borated product has 1.14 percent nitrogenand 0.68 percent boron by weight for a B/N ratio of 0.596 to 1.0. Thislubricant oil formulation is called Oil A. The second comparativelubricant oil formulation is an accepted SAE reference 10W30 oil and ishereafter referred to as SAE Reference Oil.

Lincoln test results Example SAE Pass 1 Oil A Reference Oil Sludge:

Rocker Arm Assembly 8. 4 6.1 4. 7 Rocker Arm Cover 7. 7 5. 8 4. TopEngine Cover 6.5 6.1 3. 3 Oil Screen 10.0 9. 7 2. 0 Oil Pan 0. 4 7.0 0.1Push Rod Chamber 0.0 (3.9 4.0 Timing Gear Cover. 8.9 7.7 4.8 Valve Deck6. 4 3. 8

% Total (28.0 minimum) 42. 8 34. 6 21.1

Varnish:

Piston, Avg. (7.0 min.) 9. 0 8.0 5. 5 Rocker Arm Cover 7. Z 6. 4 8.1 TopEngine Cover. 8.6 7.6 8. 2 Oil Pan 9.4 6.6 7. 6 Cylinder Walls (13 RT).9.0 6. 2 8. 0

Total 43.2 34.8 37.4

Ring Sticking Oil Ring Clogging, pcrcent 2 50 14 99 Oil Screen Plugging,percent 60 3 Valve Lifter Sticking" Valve Lifter Varnish... 0.8 OilConsumption, Qts. 2 8. 0 7.0 6.8 9.2

1 None. 2 Maximum.

Oxidation stability test Oxidation stability, that is, the resistance ofan oil to piston varnish deposit formation and bearing corrosion, isevaluated in the CLR L-38 engine test. This utilizes a single cylinderLabeco oil test engine operated at 3,150 r.p.rn. with the oiltemperature at 300 F. and the water temperature at 195 F. At the testconclusion, the copperlead connecting rod bearings are weighed; bearingweight loss (BWL) should be less than 50 milligrams. The piston isvisually evaluated according to a scale of 1 to 10; 10 represents aperfectly clean and varnish-free piston. Oil formulation of Example 1 istested for 40 hours in a CLR L-38 engine. Total varnish or total sludgeratings of 50 indicates a clean engine.

The following results are observed:

L-38 oxidation stability test 40 hrs. Total sludge 50.0 Piston varnish9.9 Total varnish 48.9 Whole bearing Weight loss, mg. 19.6

Similated PC V valve test A 1963 Falcon 170 cubic inch displacementengine with oil filter, oil cooler, and an ice water cooled condenser inthe crankcase vent line between the crankcase and intake manifold isoperated with the lubricant oil formulation of this invention describedin Example 1. The condenser in the crankcase vent line is operated underconditions which cause substantially all condensable materials to bereturned to the crankcase thus providing conditions which are as severeas, if not more severe than, complete PCV valve plugging especially withrespect to the severity of corrosive-wear in the valve train. The use ofsuch a condenser under the type of engine operation hereinafterdescribed similating severe stop-and-go driving is an accelerated PCVvalve test since the engine is always operating under conditions whichoccur at PCV valve plugging rather than condi- 13 tions starting with aclean, fully operating PCV valve and progressing through 100% PCV valveplugging.

The engine is started and operated for 45 minutes at no load, 500:25r.p.m., 115i5 F. coolant exit temperature and with oil sump temperatureof 125 F. maximum. Then the engine is operated for two hours at a 30horsepower load (about 50% load) at 2,500125 r.p.m. with 125:5" F.collant exit temperature and crankcase oil sump at 175 F. temperature.These no load and 30 horsepower load operations are repeated alternatelyfive times per day for a total of 13 hours and 45 minutes of run time.Then the engine is stopped for hours and minutes. The entire procedureis run for 4 days (total of 55 hours run time).

After the above-described four-day test the lifter, plungers, lifterbarrels and push rods are examined for rust and the valve tips measuredfor Wear. On the basis of a rating scale of 0 to 10 where the value of10 indicates no rust, i.e., clean parts, the average rust rating of theaforementioned valve train parts was 9.4.

Lubricating oil formulation of Example 1 was tested in a 1964 Ford V-8engine of 289 cubic inch displacement following a modified LincolnSequence V technique- The engine is equipped with a positive crankcaseventilation valve and is operated according to the following three-stagecycle.

1st Stage 2nd Stage 3d Stage Time, minutes 45 120 75 Speed, r.p.m 500i252, 500:1;25 2, 500:1;25 Load, BMEP. 1 2 95i2 2 955:2 Water exit, F-115i5 12515 170:1;5 Oil Tempelatur 12515 17515 205:1;5 Air'Fuel 3 9.510. 5 4 15. 5:1;0. 5 4 15. 511:0. 5

1 No load.

2 182 foot pounds or 86.6 O.B.H.P.

= Rich.

4 Lean.

The positive crankcase ventilation (PCV) valve is checked initially andevery 32 hours thereafter but is not cleaned during 192 hours ofoperation (a total of 48 cycles). Oil consumption should not exceed 7quarts for the 192 hours. After 192 hours the engine is disassembled andits parts are examined and rated as in the Lincoln Sequence V Test. Themain results of this test were as follows:

192 Hour-289 cubic inch Ford engine test It will be understood that thisinvention is not based on the discovery of any one of the disclosedoil-soluble nitrogen-boron-containing dispersant-detergent, the alkalineearth metal salts of hydrocarbon sulfonic acids or the heat stable zincdialkyldithiophosphates as new compositions of matter or theirindividual usefulness as addition agents in lubricant oil compositions.Rather this invention is based on the discovery of a lubricant oilcomposition useful for the severe service function imposed by long drainlife which composition comprises a major proportion of a hydrocarbonlubricating oil and an essential combination consisting of the disclosed(a) oilsoluble nitrogen-boron-containing dispersant-detergent, (b) thealkaline earth metal salt of hydrocarbon sulfonic acid and (c) the zincdialkyldithiophosphate in the amounts for each gallons of lubricant oilcomposition. It will also be understood that other individual additionagents having functions other than the functions of the three essentialaddition agents can be added to the lubricant oil composition of thisinvention in amounts that do not eifect the character and nature of thecombination of the three essential addition agents. Such other additionagents include for example anti-foam agents, lubricating agents andviscosity index improvement agents.

Therefore, that claimed as invention is:

1. A lubricant oil composition comprising a major portion of ahydrocarbon lubricating oil and the combination of essential additivesconsisting of (a) an oil-soluble nitrogen-boron-containingdetergent-dispersant that is the boric acid borated derivative of adi(alkenylsuccinimide) of a symmetrical bis(amino-polyazethyl)substituted urea which disuccinimide is the product of an alkenylhydrocarbon substituted succinic anhydride whose alkenyl substituent hasfrom 30 to 200 carbon atoms reacted under conditions splitting out andremoving water with the symmetrical bis substituted urea in the ratio oftwo moles of the substituted succinic anhydride per mole of thesymmetrical bis substituted urea and the urea reactant is the product ofa polyethylene polyamine having the formula wherein x is a number from 2to 6 inclusive, condensed with urea in the ratio of about two moles ofthe polyamine per mole of urea under conditions splitting out andremoving tWo moles of ammonia per mole of urea, and thedetergent-dispersant has an amount of boron related to the nitrogen inthe ratio of 0.1 to 0.5 boron per 1.0 nitrogen on a weight basis;

(b) an oil-soluble alkaline earth metal salt of a hydrocarbon sulfonicacid whose hydrocarbon group contains an alkyl group of at least 30carbon atoms and the salt has an alkalinity equivalent to a total basenumber of at least 300 milligrams KOH per gram; and

(c) a heat stable zinc dialkyldithiophosphate of whose two dialkylgroups one is an isopropyl or primary butyl group and the other is aprimary alkyl group of 5 to 10 carbon atoms in size, in the amounts foreach 100 gallons of lubricant oil composition of 3 to 20 pounds of theoil-soluble nitrogen-boron detergent-dispersant (a), the amount ofalkaline earth metal salt (b) chemically equivalent to 1.05 to 3.2pounds of calcium and an amount of zinc salt (0) to provide 0.25 to 1.2pounds zinc.

2. The composition of claim 1 wherein magnesium salt of a hydrocarbonsulfonic acid is alkaline earth metal salt additive (b).

3. The composition of claim 2 wherein additive (a) the alkenylsubstituted succinic anhydride reactant has a molecular weight of from860 to 960 inclusive and the alkenyl substituent group is a polybutenylgroup derived from a liquid viscous polybutene and tetraethylenepentamine is the polyethylene polyamine raactant for the symmetricallybis substituted urea reactant.

References Cited UNITED STATES PATENTS 3,000,822 9/1961 Higgins et a1.25232.7 3,076,841 2/1963 Hutchings et a1. 252-33 XR 3,087,936 4/1963 LeSuer 25249.6 2G1 3,340,190 9/1967 Delu-ga et al. 25233.4

DANIEL E. WYMAN, Primary Examiner.

P. P. GARVIN, Assistant Examiner.

